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A game is played using two spinners. Spinner A has four sections labelled 2, 4, 6, 8 and Spinner B has labelled 1, 3, 5. Players spin both spinners and add the numbers together. B) the game is used in a school to raise money for charity. Each player plays 20p to play the game. To win a lolly pop you have to score a 7 exactly, and each of these lolly pops costs the school 30p. How much should the school expect to raise if 120 kids play the game ?

Respuesta :

Answer:

1500p

Step-by-step explanation:

The spinner A has 4 possible values, and the spinner B has 3 possible values, so the total number of possibilities for both spinners is the product of these number of possibilities:

4 * 3 = 12

From these 12 possible pair of values, the ones that give a sum of 7 are:

(6,1), (4,3) and (2,5).

We have 3 cases where the sum is 7, so the probability of having a sum of 7 is 3/12 = 25%. Therefore, the probability of not having a sum of 7 is 75%

To find the expected value, we multiply the probability of each case by the value it would give. If the player wins, the school loses 10p (the player paid 20p and earned 30p), and if the player loses, the school wins 20p. So the expected value of 120 games is:

120 * (0.25 * (-10) + 0.75 * (20)) = 1500p

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